diff --git a/store/localstore/txn.go b/store/localstore/txn.go
index e31ff236be..4a30423d5d 100644
--- a/store/localstore/txn.go
+++ b/store/localstore/txn.go
@@ -231,7 +231,7 @@ func (txn *dbTxn) Commit() error {
 		txn.close()
 	}()
 
-	return txn.doCommit()
+	return errors.Trace(txn.doCommit())
 }
 
 func (txn *dbTxn) CommittedVersion() (kv.Version, error) {
diff --git a/structure/hash.go b/structure/hash.go
index 3162e819c4..5195c945a8 100644
--- a/structure/hash.go
+++ b/structure/hash.go
@@ -92,34 +92,40 @@ func (t *TxStructure) HGetInt64(key []byte, field []byte) (int64, error) {
 }
 
 func (t *TxStructure) updateHash(key []byte, field []byte, fn func(oldValue []byte) ([]byte, error)) error {
-	metaKey := t.encodeHashMetaKey(key)
-	meta, err := t.loadHashMeta(metaKey)
-	if err != nil {
-		return errors.Trace(err)
-	}
-
 	dataKey := t.encodeHashDataKey(key, field)
-	var oldValue []byte
-	oldValue, err = t.loadHashValue(dataKey)
+	oldValue, err := t.loadHashValue(dataKey)
 	if err != nil {
 		return errors.Trace(err)
 	}
 
-	if oldValue == nil {
-		meta.Length++
-	}
-
-	var newValue []byte
-	newValue, err = fn(oldValue)
+	newValue, err := fn(oldValue)
 	if err != nil {
 		return errors.Trace(err)
 	}
 
+	// Check if new value is equal to old value.
+	if bytes.Equal(oldValue, newValue) {
+		return nil
+	}
+
 	if err = t.txn.Set(dataKey, newValue); err != nil {
 		return errors.Trace(err)
 	}
 
-	return errors.Trace(t.txn.Set(metaKey, meta.Value()))
+	metaKey := t.encodeHashMetaKey(key)
+	meta, err := t.loadHashMeta(metaKey)
+	if err != nil {
+		return errors.Trace(err)
+	}
+
+	if oldValue == nil {
+		meta.Length++
+		if err = t.txn.Set(metaKey, meta.Value()); err != nil {
+			return errors.Trace(err)
+		}
+	}
+
+	return nil
 }
 
 // HLen gets the number of fields in a hash.
diff --git a/structure/structure_test.go b/structure/structure_test.go
index 3b1afd348d..76c2cdd13c 100644
--- a/structure/structure_test.go
+++ b/structure/structure_test.go
@@ -193,7 +193,7 @@ func (s *tesTxStructureSuite) TestHash(c *C) {
 
 	value, err = tx.HGet(key, []byte("fake"))
 	c.Assert(err, IsNil)
-	c.Assert(err, IsNil)
+	c.Assert(value, IsNil)
 
 	keys, err := tx.HKeys(key)
 	c.Assert(err, IsNil)
@@ -224,13 +224,41 @@ func (s *tesTxStructureSuite) TestHash(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(l, Equals, int64(2))
 
+	// Test set new value which equals to old value.
+	value, err = tx.HGet(key, []byte("1"))
+	c.Assert(err, IsNil)
+	c.Assert(value, DeepEquals, []byte("1"))
+
+	err = tx.HSet(key, []byte("1"), []byte("1"))
+	c.Assert(err, IsNil)
+
+	value, err = tx.HGet(key, []byte("1"))
+	c.Assert(err, IsNil)
+	c.Assert(value, DeepEquals, []byte("1"))
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(2))
+
 	n, err = tx.HInc(key, []byte("1"), 1)
 	c.Assert(err, IsNil)
 	c.Assert(n, Equals, int64(2))
 
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(2))
+
+	n, err = tx.HInc(key, []byte("1"), 1)
+	c.Assert(err, IsNil)
+	c.Assert(n, Equals, int64(3))
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(2))
+
 	n, err = tx.HGetInt64(key, []byte("1"))
 	c.Assert(err, IsNil)
-	c.Assert(n, Equals, int64(2))
+	c.Assert(n, Equals, int64(3))
 
 	l, err = tx.HLen(key)
 	c.Assert(err, IsNil)
@@ -246,6 +274,55 @@ func (s *tesTxStructureSuite) TestHash(c *C) {
 	err = tx.HDel(key, []byte("fake_key"))
 	c.Assert(err, IsNil)
 
+	// Test set nil value.
+	value, err = tx.HGet(key, []byte("nil_key"))
+	c.Assert(err, IsNil)
+	c.Assert(value, IsNil)
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(0))
+
+	err = tx.HSet(key, []byte("nil_key"), nil)
+	c.Assert(err, IsNil)
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(0))
+
+	err = tx.HSet(key, []byte("nil_key"), []byte("1"))
+	c.Assert(err, IsNil)
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(1))
+
+	value, err = tx.HGet(key, []byte("nil_key"))
+	c.Assert(err, IsNil)
+	c.Assert(value, DeepEquals, []byte("1"))
+
+	err = tx.HSet(key, []byte("nil_key"), nil)
+	c.Assert(err, NotNil)
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(1))
+
+	value, err = tx.HGet(key, []byte("nil_key"))
+	c.Assert(err, IsNil)
+	c.Assert(value, DeepEquals, []byte("1"))
+
+	err = tx.HSet(key, []byte("nil_key"), []byte("2"))
+	c.Assert(err, IsNil)
+
+	l, err = tx.HLen(key)
+	c.Assert(err, IsNil)
+	c.Assert(l, Equals, int64(1))
+
+	value, err = tx.HGet(key, []byte("nil_key"))
+	c.Assert(err, IsNil)
+	c.Assert(value, DeepEquals, []byte("2"))
+
 	err = txn.Commit()
 	c.Assert(err, IsNil)